To validate DEGs identified from microarray studies, expression of selected genes was measured by qRT-PCR from an independent aliquot of RNA to that used for the microarray analysis. We first studied the expression of previously reported candidate genes from the literature on genetic studies of BPD: ANK3, ODZ4 and CACNA1C [44–46]. Consistent with the microarray data, qRT-PCR failed to show alterations in the expression of these genes in BPD versus control samples (Fig 5A–5C). We also examined the expression of mRNA encoding GSK3β, a molecule implicated in the mechanism of therapeutic response to lithium [42, 47], which showed small changes (Fold change of BPD_L/CTRL_L = 1.6) in the microarray, but failed to show a significant difference by qRT-PCR (Fig 5D). Voltage gated type IV sodium channel beta subunit, SCN4B, was identified as one of the highly down-regulated genes by the microarray in L neurons of BPD samples (fold change = -14.6). Expression of SCN4B mRNA also showed a decrease by qRT-PCR, but did not reach statistical significance due to high variability between samples (Fig 5E). Glutamate decarboxylase 1 (GAD1) showed 2.5-fold increase in the microarray analysis of L neurons, which was confirmed by qRT-PCR (Fig 5F).
